1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
#include <iostream>
#include <unordered_map>
#include <algorithm>


using namespace std;

int findCollisions(unordered_map<int, int> &horizontal, unordered_map<int, int> &vertical) {
    int ret = 0;
    for (auto &hcar: horizontal) {
        int offset = hcar.first;
        if (vertical.find(offset) != vertical.end()) {
            ret += min(hcar.second, vertical[offset]);
        }
    }
    return ret;
}


int main() {
    int n;
    int ti;
    int wi;
    int ri;
    cin >> n;
    auto horizontal = unordered_map<int, int>();
    auto vertical = unordered_map<int, int>();
    for (int i = 0; i < n; i++) {
        cin >> ti >> wi >> ri;
        int offset = wi - ri;
        if (ti == 1) {
            vertical[offset] += 1;
        } else {
            horizontal[offset] += 1;
        }
    }

    int result = findCollisions(horizontal, vertical);
    cout << result << std::endl;
    return 0;
}